Diaphragm chuck



Patented Jan. 16, 1951 UNITED STATES PATENT orncs DIAPHRAGM CHUCK Merton H. Arms, Springfield, Vt., assignor to Bryant Chucking Grinder Company, Springfield, Vt., a corporation of Vermont Application March 1'7, 1947, Serial No. 735,052

3 Claims. 1

This invention relates to chucks of the dip'hragm type and has for an object to provide such a chuck which is not liable to release the work when rotated at a high speed due to the action of centrifugal force on the work-gripping parts of the chuck.

A further object of the invention is to provide a diaphragm chuck which has two sets of Work. grippers either of which may be rendered operative so that work pieces of widely differentsizes or configurations may be held by the one chuck. For example, one of the sets of work grippers may engage a work piece externally and the other set may engage an internal face of a work piece. The particular set of work grippers not in operation at any time are employed to counterbalance the effects of centrifugal force on the work grippers which are in operation, or if desired toover balance.

For a complete understanding of this invention, reference may be had to the accompanying drawings in which Figure 1 is a front elevation of a chuck embodying the invention.

Figure 2 is a sectional view on line 2-2 of Figure 1 and showing an externally clamped work piece.

Figure 3 is a view similar to Figure 2, but showing the work-engaging diaphragm reversed and engaging the inner walls of a work piece.

Figures 4 and 5 are fragmentary views similar to a portion of Figure 2, but showing work pieces of different size engaged by reverse positioning of the diaphragm.

At l is shown a rotary hollow work spindle through which is slidable a work-releasing rod 2. The spindle i has a nose 3 on its forward end to which may be attached the chuck. This chuck comprises a rear face plate portion 4 which may be secured to the nose 3, as bythe screws 30., this face plate portion having a forwardly projecting housing 5. To the forward edge of this housing there is secured, as by screws 6, a diaphragm I. This diaphragm has a series of radial angularly spaced forwardly extending fingers 8 to the inner face of which may be adiustably secured, as by screws 9, a plurality of work-gripping segments Iii. These segments may be held in work holding position for grinding their work-engaging faces by a ring ll, shown in dotted lines, the ring holding the segments slightly sprung open so that they grip the ring; This ring is thereafter removed and is not used during normal operation of the chuck. The elements ID are of such thickness that the return of the diaphragm 1 toward normal unstressed condition causes them to engage and grip the outer face of the work piece l4.

The rod 2 has a reduced extremity IE to which issecured a head I6 having a threaded shank IT. A reduced diameter portion P8 of this head projects through an opening 20 centrally positioned through the diaphragm I. By moving the rod 2 in the direction of the arrow shown in Figure 2, the mid-portion of the diaphragm is flexed outwardly, rocking the jaws l0 outwardly and freeing the work piece.

It will be noted, however, that centrifugal. force acting on the jaws 8 and the blocks It] would normally tend to separate thev gripping blocks l0 and thus free the work therefrom when the work is rotated at a substantial speed. In order to prevent this the diaphragm I is provided with radially arranged fingers '25 which extend into the space between the diaphragm 1 and the face plate portion 4 afforded by the housing 5. Centrifugal force acting on these fingers 25 is in reverse direction to centrifugal force acting on the fingers 8 and this centrifugal force on the two sets of fingers may be substantially equalized, if desired or necessary, counterweights 26 being secured to the rearwardly extended fingers 25 for this purpose. Under such conditions rotation of the spindle will have no tendency to release the work.

This construction, however, has a further advantage'in that it permits reversal end for end of the diaphragm I so that either set of fingers 8 or 25 may be arranged to grip the work and the other set to counterbalance the first set. Thus in Figure 3 the fingers 25 are positioned outwardly while the fingers 8 are the counterbalance fingers, and as shown in Figure 3, the fingers 25 may be provided with external segmental clamping blocks 21 which may be engaged with the inner wall of the work piece 28. If suitable, the counterbalance weights 26 of Figure 2 and the clamping bars 21 of Figure 3 may be the same elements. In order to release the work piece 28, the rod 2 is moved to the left so that the head portion l6 engages the diaphragm I and deflects it in the opposite direction to its action in Figure 2, flexing of the diaphragm in this direction, serving to move the clamping blocks 21 inwardly toward each other to free the work.

A ring Ila, shown in dotted lines in Figure 3, may be employed when grinding the work-engaging faces of the external segmental clamping blocks 21 tohold the fingers 25 slightly closed,

this ring Ila being thereafter removed and not used during normal operation of the chuck.

In Figures 4 and 5 each set of fingers 8 and 25 are employed when outwardly positioned, for engagement with the outer face of the work, but the effective internal diameters of the clamping blocks 30 and 3| may be different so that a relatively large :diameter ,piece 35.:may'be grippediby the fingers '8 "with their clamping b1ocks'30 as shown in Figure 5, and a relatively small diameter work piece such as 36, may be engaged *by the blocks 3| when the fingers 25 are-employed as the forwardly extending gripping elements.

If desired the inner fingers mayibe weightedtto returning it to clamping=position as soon as the pressure'ofthe rod 2 thereonis released. :As is :customary with diaphragm chucks, one or more *stop bars 40 having their rear ends threaded into athe (face plate portion 4 and extending through a perforation 4| in thesdi'aphragm, may :be employed to limit the extent :to which tithe work piece "may be thrust :backwardly between "the clamping blocks, this being :shown .in "FigureL-2.

From the "foregoing description 'of certain embodiments of this invention it willbe understood by those skilled 'in the art that "various further changes and modifications might be made with- "outdepartingfrom its spirit orscope.

I -claimt 1. A diap'hragm chuck including a faceplate for attachment to a spindle nose, a diaphragm, means supporting said diaphragm forwardly 0f and spaced "from said "face plate'and either side out, aset of angularly spaced fingers extending outwardly from opposite faces of'said diaphragm,

the fingers of each setsubstantially counterbalancing the effects of centrifugal force on theifin- 'gers of the other set as "the chuck is revolved about its axis, the fingers of eachset when-extended away from said face plate 'being positioned to-engage a workpiece, and means for flexing -=said diaphragm by pressure exerted :axially substantially centrally thereon to retract such-fingers from and "free the work piece.

2. A diaphragm chuck including a face plate for attachment to a spindle nose, a diaphragm, means supporting said diaphragm forwardly of and spaced from said face plate and either side out, a set of angularly spaced fingers extending away from each of opposite faces of said diaphragm, the fingers of each set substantially ,counterbalancing the :e'fiects of centrifugal force on the fingers of the'other *set tending to flex said diaphragm as the chuck is revolved about its axis, the fingers of each set when extended awayfrom said face plate being positioned to engage a work piece, the fingers of one set having inwardly facing awork-engaging portions to engage an external 'face of a work piece and the fingers of the other set having outwardly facing -work.-.engagin g ..portions arranged to engage an internal face of a work piece, and means for flexing said diaphragm by pressure exerted axially substantially centrally thereon to retract such fingers from and freethework piece.

.13. A diaphragm'chuck including a face plate 51'01 gattachment' to .aispindlenose, a diaphragm, :means supporting said diaphragm forwardly of andspaced from said face plate and with either side facing outwardly, a set of angularly spaced V-fingers extending outwardly from each of oppov:sitefacesof.sai'ddiaphragm, the fingers of 'each set substantially counterbalancing the effects of (centrifugal forceonthe fingers of the other set :as the chuck is revolvedabout its axis, the finz ers of the :two sets having their-outer portions zarranged. normally --s pa ced apart by differentv dista 110652170 engage work faces of different diamzeters and 517116 ifingers :Of each .set when extended awayfrom said face plate being positioned to :engage-a work,piece, and'meansfor flexing said :diaphragm bypressure exerted axially substantially centrally thereon to retract such 'fingers from and'freel the workpiece.

MERTON H. ARMS.

REFERENCES CITED The followingreferences are of record in the ,file of this patent:

UNITED STATES PATENTS 

